1. Field of the Invention
The present invention relates to a semiconductor device and method of manufacture thereof, circuit board, and electronic instrument.
2. Description of Related Art
With the increasingly compact nature of electronic instruments, semiconductor devices are known with a stacked construction incorporating a plurality of substrates (interposers) on which semiconductor chips are mounted laminated at high density. By means of this, the area of the circuit board (motherboard) on which the semiconductor devices are mounted is utilized efficiently, and an electronic instrument which is more compact and of high density can be manufactured.
For example, in Japanese Patent Application Laid-Open No. 8-236694, in a semiconductor device of stacked construction, connector terminals connecting upper and lower semiconductor chips are disposed on the extremity of a substrate to avoid a semiconductor chip disposed in a central portion. Then the circuit board and semiconductor device of stacked construction are electrically connected by connector terminals provided at the extremity of the substrate, in the same way that upper and lower semiconductor chips are connected.
However, according to this form of connection of the semiconductor device to the circuit board, since the pitch of the terminals for connection of the semiconductor device to the circuit board is fine, an expensive circuit board fine interconnecting lines must be used. By means of this, it is difficult to position the semiconductor device on the circuit board, and because of this the yield when the semiconductor device is mounted may be reduced.
Furthermore, since the connector terminals disposed at the extremity of the substrate are formed outside the semiconductor chip, if the pitch of the connector terminals is increased, there is a problem in that the area of the circuit board occupied by the semiconductor device also increases.
A semiconductor device according to the first aspect of the present invention comprises:
a plurality of semiconductor chips; and
a plurality of substrates, each of the substrates having one of the semiconductor chips mounted thereon,
wherein:
the substrates are stacked each other;
upper and lower ones of the semiconductor chips mounted on a pair of the stacked substrates are electrically connected through first terminals provided in a region outside the region in which one of the semiconductor chips is mounted in each of the substrates;
the lowest one of the substrates has second terminals provided in its region closer to its center than its region in which the first terminals are provided, the second terminals electrically connected to one of the semiconductor chips; and
a pitch of adjacent two of the second terminals is wider than a pitch of adjacent two of the first terminals.
A circuit board according to the second aspect of the present invention has the above-mentioned semiconductor device mounted thereon, and the semiconductor device is electrically connected to the circuit board through the second terminals.
An electronic instrument according to the third aspect of the present invention has the above-mentioned semiconductor device.
A method of manufacture of a semiconductor device according to the fourth aspect of the present invention comprises the steps of:
stacking a plurality of substrates, each of the substrates having one of semiconductor chips mounted thereon, each of the substrates having an outline larger than each of the semiconductor chips; and
electrically connecting upper and lower ones of the semiconductor chips through first terminals provided in a region outside the region in which one of the semiconductor chips is mounted in each of the substrates,
wherein the lowest one of the substrates has second terminals provided in its region closer to its center than the first terminals, the second terminals are electrically connected to one of the semiconductor chips, and a pitch of adjacent two of the second terminals is wider than a pitch of adjacent two of the first terminals.
According to the present invention, a semiconductor device of stacked construction which can easily be mounted on a circuit board can be manufactured.